[PATCH] soundwire: bus_type: fix remove and shutdown support

[PATCH] soundwire: bus_type: fix remove and shutdown support

[Bard Liao]

From: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>

The bus sdw_drv_remove() and sdw_drv_shutdown() helpers are used
conditionally, if the driver provides these routines.

These helpers already test if the driver provides a .remove or
.shutdown callback, so there's no harm in invoking the
sdw_drv_remove() and sdw_drv_shutdown() unconditionally.

In addition, the current code is imbalanced with
dev_pm_domain_attach() called from sdw_drv_probe(), but
dev_pm_domain_detach() called from sdw_drv_remove() only if the driver
provides a .remove callback.

Fixes: 9251345dca24b ("soundwire: Add SoundWire bus type")
Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Reviewed-by: Rander Wang <rander.wang@intel.com>
Signed-off-by: Bard Liao <yung-chuan.liao@linux.intel.com>
---
 drivers/soundwire/bus_type.c | 8 ++------
 1 file changed, 2 insertions(+), 6 deletions(-)

diff --git a/drivers/soundwire/bus_type.c b/drivers/soundwire/bus_type.c
index 893296f3fe39..b81e04dd3a9f 100644
--- a/drivers/soundwire/bus_type.c
+++ b/drivers/soundwire/bus_type.c
@@ -193,12 +193,8 @@ int __sdw_register_driver(struct sdw_driver *drv, struct module *owner)
 
 	drv->driver.owner = owner;
 	drv->driver.probe = sdw_drv_probe;
-
-	if (drv->remove)
-		drv->driver.remove = sdw_drv_remove;
-
-	if (drv->shutdown)
-		drv->driver.shutdown = sdw_drv_shutdown;
+	drv->driver.remove = sdw_drv_remove;
+	drv->driver.shutdown = sdw_drv_shutdown;
 
 	return driver_register(&drv->driver);
 }
-- 
2.17.1

Re: [PATCH] soundwire: bus_type: fix remove and shutdown support

[Vinod Koul]

On 10-06-22, 09:51, Bard Liao wrote:
> From: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
> 
> The bus sdw_drv_remove() and sdw_drv_shutdown() helpers are used
> conditionally, if the driver provides these routines.
> 
> These helpers already test if the driver provides a .remove or
> .shutdown callback, so there's no harm in invoking the
> sdw_drv_remove() and sdw_drv_shutdown() unconditionally.

Okay sounds good

> In addition, the current code is imbalanced with
> dev_pm_domain_attach() called from sdw_drv_probe(), but
> dev_pm_domain_detach() called from sdw_drv_remove() only if the driver
> provides a .remove callback.

Am not sure I follow what is imbalance, pm_domain_attach/detach?

> Fixes: 9251345dca24b ("soundwire: Add SoundWire bus type")

How is this a fix is still unclear to me. At best I think this is code
optimization and removing checks which maybe redundant.

> Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
> Reviewed-by: Rander Wang <rander.wang@intel.com>
> Signed-off-by: Bard Liao <yung-chuan.liao@linux.intel.com>
> ---
>  drivers/soundwire/bus_type.c | 8 ++------
>  1 file changed, 2 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/soundwire/bus_type.c b/drivers/soundwire/bus_type.c
> index 893296f3fe39..b81e04dd3a9f 100644
> --- a/drivers/soundwire/bus_type.c
> +++ b/drivers/soundwire/bus_type.c
> @@ -193,12 +193,8 @@ int __sdw_register_driver(struct sdw_driver *drv, struct module *owner)
>  
>  	drv->driver.owner = owner;
>  	drv->driver.probe = sdw_drv_probe;
> -
> -	if (drv->remove)
> -		drv->driver.remove = sdw_drv_remove;
> -
> -	if (drv->shutdown)
> -		drv->driver.shutdown = sdw_drv_shutdown;
> +	drv->driver.remove = sdw_drv_remove;
> +	drv->driver.shutdown = sdw_drv_shutdown;
>  
>  	return driver_register(&drv->driver);
>  }
> -- 
> 2.17.1

-- 
~Vinod

Re: [PATCH] soundwire: bus_type: fix remove and shutdown support

[Pierre-Louis Bossart]

On 6/23/22 02:55, Vinod Koul wrote:
> On 10-06-22, 09:51, Bard Liao wrote:
>> From: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
>>
>> The bus sdw_drv_remove() and sdw_drv_shutdown() helpers are used
>> conditionally, if the driver provides these routines.
>>
>> These helpers already test if the driver provides a .remove or
>> .shutdown callback, so there's no harm in invoking the
>> sdw_drv_remove() and sdw_drv_shutdown() unconditionally.
> 
> Okay sounds good
> 
>> In addition, the current code is imbalanced with
>> dev_pm_domain_attach() called from sdw_drv_probe(), but
>> dev_pm_domain_detach() called from sdw_drv_remove() only if the driver
>> provides a .remove callback.
> 
> Am not sure I follow what is imbalance, pm_domain_attach/detach?

Yes, the dev_pm_domain_detach() is done conditionally, depending on the
presence of a driver .remove callback, that's not so good.

>> Fixes: 9251345dca24b ("soundwire: Add SoundWire bus type")
> 
> How is this a fix is still unclear to me. At best I think this is code
> optimization and removing checks which maybe redundant.

I think the Fixes tag is appropriate for the dev_pm_domain_detach()
problem, but if you want to drop it that's fine with me.


>> Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
>> Reviewed-by: Rander Wang <rander.wang@intel.com>
>> Signed-off-by: Bard Liao <yung-chuan.liao@linux.intel.com>
>> ---
>>  drivers/soundwire/bus_type.c | 8 ++------
>>  1 file changed, 2 insertions(+), 6 deletions(-)
>>
>> diff --git a/drivers/soundwire/bus_type.c b/drivers/soundwire/bus_type.c
>> index 893296f3fe39..b81e04dd3a9f 100644
>> --- a/drivers/soundwire/bus_type.c
>> +++ b/drivers/soundwire/bus_type.c
>> @@ -193,12 +193,8 @@ int __sdw_register_driver(struct sdw_driver *drv, struct module *owner)
>>  
>>  	drv->driver.owner = owner;
>>  	drv->driver.probe = sdw_drv_probe;
>> -
>> -	if (drv->remove)
>> -		drv->driver.remove = sdw_drv_remove;
>> -
>> -	if (drv->shutdown)
>> -		drv->driver.shutdown = sdw_drv_shutdown;
>> +	drv->driver.remove = sdw_drv_remove;
>> +	drv->driver.shutdown = sdw_drv_shutdown;
>>  
>>  	return driver_register(&drv->driver);
>>  }
>> -- 
>> 2.17.1
> 

Re: [PATCH] soundwire: bus_type: fix remove and shutdown support

[Vinod Koul]

On 23-06-22, 09:54, Pierre-Louis Bossart wrote:
> 
> 
> On 6/23/22 02:55, Vinod Koul wrote:
> > On 10-06-22, 09:51, Bard Liao wrote:
> >> From: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
> >>
> >> The bus sdw_drv_remove() and sdw_drv_shutdown() helpers are used
> >> conditionally, if the driver provides these routines.
> >>
> >> These helpers already test if the driver provides a .remove or
> >> .shutdown callback, so there's no harm in invoking the
> >> sdw_drv_remove() and sdw_drv_shutdown() unconditionally.
> > 
> > Okay sounds good
> > 
> >> In addition, the current code is imbalanced with
> >> dev_pm_domain_attach() called from sdw_drv_probe(), but
> >> dev_pm_domain_detach() called from sdw_drv_remove() only if the driver
> >> provides a .remove callback.
> > 
> > Am not sure I follow what is imbalance, pm_domain_attach/detach?
> 
> Yes, the dev_pm_domain_detach() is done conditionally, depending on the
> presence of a driver .remove callback, that's not so good.

Sorry am bit confused now, this is what I have in sdw-next

static int sdw_drv_remove(struct device *dev)
{
        struct sdw_slave *slave = dev_to_sdw_dev(dev);
        struct sdw_driver *drv = drv_to_sdw_driver(dev->driver);
        int ret = 0;

        if (drv->remove)
                ret = drv->remove(slave);

        dev_pm_domain_detach(dev, false);

        return ret;
}

I see that dev_pm_domain_detach() is called unconditionally and not
dependent on remove method which seems right to me.

The code seems same since 9251345dca24b

-- 
~Vinod

Re: [PATCH] soundwire: bus_type: fix remove and shutdown support

[Vinod Koul]

On 04-07-22, 11:13, Vinod Koul wrote:
> On 23-06-22, 09:54, Pierre-Louis Bossart wrote:

> I see that dev_pm_domain_detach() is called unconditionally and not
> dependent on remove method which seems right to me.
> 
> The code seems same since 9251345dca24b

And I overlooked the setting of method, which is correct, sorry for the
noise.

Have applied this now, thanks

-- 
~Vinod